Linear motion driving devices may be used in many mechanical structures, and the sprocket/push-chain driving device is one of these. Sprocket/push-chain driving devices may include a push-chain, a sprocket and a guiding component. One end of the push-chain has a connecting part, and another end of the push-chain passes around the sprocket and is placed freely. When the sprocket rotates, the sprocket drives the push-chain to move. The guiding component is in contact with the push-chain and is used to guide the push-chain to move in a set linear direction. The sprocket/push-chain driving devices may also include a push-chain box for accommodating the sprocket and the freely placed end of the push-chain.
Existing push-chains may be assembled from a relatively large number of chain sections of different shapes and have disadvantages such as, for example, a relatively high cost and complicated assembly.
The Chinese patent application with application no. 20082013537.4 discloses a vertical motion driving device of the sprocket/push-chain type for a patient table. As FIG. 1 shows, this vertical motion driving device includes a push-chain 1, a sprocket 2, guiding components 3 and a push-chain box 4. The section of the push-chain 1 that is arranged in the vertical direction is used to support a bed board of the patient table. The sprocket 2 and the push-chain 1 are meshed with one another. The sprocket 2 is capable of driving the push-chain 1 to move when the sprocket 2 rotates, such that the push-chain 1 drives the bed board in up/down vertical motion under the action of the guiding components.
Chinese patent application no. 20082000631.4 discloses a horizontal motion driving device of the sprocket/push-chain type for a patient table. This device similarly includes a sprocket, a push-chain, guiding components, and a push-chain box. One end of the push-chain has a connecting part for connecting to the bed board of the patient table, while the other end passes around the sprocket and is placed freely. When the sprocket rotates, the sprocket drives the push-chain in reciprocal horizontal motion, thereby making the push-chain drive the bed board in reciprocal horizontal motion under the action of the guiding components.